Photochromism in organic systems is of interest because of potential utility in applications such as high density optical memories and optical switching devices.
Thermochromism and solvatochromism in multilayer organic systems are described in Thin Solid Films, 135 27 (1985). The organic layers in thin films are composed of merocyanine dyes.
The suitability of amphiphilic compounds which contain quaternary ammonium groups for the formation of ordered structures is described in Thin Solid Films, 121, 89 (1984).
Highly ordered bilayer films from a variety of synthetic amphiphiles which undergo spontaneous assemblage are described in Macromolecules, 18, 1515 (1985) and 20 (No. 1), 29 (1987).
Immobilization of synthetic bilayer membranes as multilayer polymer films are described in Polym. J., 16, 187 (1984).
Aqueous bilayer dispersions, cast multilayer films and Langmuir-Blodgett films of azobenzene-containing amphilphiles are described in Colloids and Surfaces, 19, 225 (1986). Methods for formation of aqueous molecular membranes as immoblized cast films are reviewed.
Molecular orientation and domain formation in surface monolayers of azobenzene-containing amphiphiles and their polyion complexes are described in Chem. Lett., 827 (1988).
Cis-trans reversible photoisomerization of an amphiphilic azobenzene derivative in a Langmuir-Blodgett film prepared as polyion complexes with polyallylamine is described in Chem. Lett., 1257 (1988).
Reversible photochromic behavior of 4-octyl-4'-(5-carboxypentamethyleneoxy) azobenzene in organized (1990).
U.S. Pat. No. 4,941,997 describes amphiphilic azo dyes which form molecular aggregate bilayer thin films which exhibit reversible thermochromic and solvatochromic properties.
Macromolecules, 24, 1041 (1991) describes Langmuir-Blodgett films of "amphotropic" molecules, i.e., preformed amphiphilic polymers containing side chain mesogenic chromophores such as stilbene, azobenzene or biphenyl structures. The Langmuir-Blodgett liquid crystalline type films exhibit a phase change to a less ordered state on heating. The reversible transition occurs at the same temperature as the onset of liquid crystal formation in the bulk material. The reference suggests that heating a Langmuir-Blodgett film of amphotropic molecules above the crystalline to liquid crystalline transition in an external magnetic or electric field can induce a monodomain formation in the film.
There is continuing interest in the development of ordered organic thin film systems which can exhibit photochromic behavior for prospective utility in all-optical data storage or spatial light modulation devices.